Horizontally translating doors usually include one or more door panels that are suspended by carriages or trolleys that travel along an overhead track. To open and close the door, the carriages move the door panels in a generally horizontal direction in front of the doorway. The movement of the panels can be powered or manually operated. Depending on the width of the doorway and the space along either side of it, such doors can assume a variety of configurations. For a relatively narrow doorway with adequate space alongside to receive an opening door panel, a single panel may be sufficient to cover the doorway. Wider doorways with limited side space may require a bi-parting door. Bi-parting doors include at least two panels, each moving in opposite directions from either side of the doorway and meeting at the center of the doorway upon closing.
For even wider doorways or those with even less side space, multi-panel doors can be used. Multi-panel doors have a series of door panels that overlay each other at one side of the doorway when the door is open. When the door closes, each panel slides out from behind the others to cover the span of the doorway. Applying such an arrangement to both sides of the doorway provides a bi-parting door with multiple panels on each side.
Horizontally translating doors are often used for providing access to freezer or cold-storage lockers, which are rooms that provide large-scale refrigerated storage for the food industry. Doorways into such a room are often rather wide to allow forklifts and other material handling equipment to move large quantities of products in and out of the room. When closing off a refrigerated room, horizontally translating doors are often preferred over other types of doors because their panels can be made relatively thick with insulation to reduce the cooling load on the room.